The present application claims the priority of the commonly owned German patent application Serial No. 100 19 930.5 filed Apr. 20, 2000 and commonly owned European patent application Serial No. 01106122.3 filed Mar. 13, 2001. The disclosures of the above-referenced priority applications, as well as that of each US and foreign patent and patent application identified in the specification of the present application, is incorporated herein by reference.
The invention relates to improvements in methods of and in apparatus for applying flowable adhesives to running strips or webs of paper or the like. More particularly, the invention relates to improvements in methods and in apparatus which can be resorted to with advantage in connection with the application of adhesive to running strips or webs (hereinafter called webs for short) of wrapping material of the type utilized in connection with the making and processing of smokers"" products.
Examples of webs of wrapping material which must be provided with layers or films of special adhesive and/or with layers or films containing different types of adhesive are those which are employed for the assembly of filter rod sections with plain cigarettes to form filter cigarettes of unit length or multiple unit length. Wrapping material of such character is known as tipping paper and is utilized in machines known as filter cigarette makers or tipping machines. Examples of such machines are those known worldwise as MAX (distributed by the assignee of the present application). A MAX machine is designed to assemble successive groups of coaxial plain cigarettes and filter rod sections of unit length or multiple unit length, to connect the constituents of such groups with each other by resorting to so-called uniting bands (sections of a web of tipping paper one side of which carries a continuous or composite film of adhesive) which are convoluted around the filter rod sectons and the adjacent end portions of plain cigarettes, and to thereafter sever the groups to obtain filter cigarettes of unit length.
German patent No. 24 45 342 C2 discloses a machine which can change the quantity of adhesive being applied to successive still coherent uniting bands of tipping paper, i.e., prior to separation of successive foremost uniting bands from the leader of a running web of tipping paper. The quantity of adhesive per uniting band is changed by reducing or increasing the thickness of the film of applied adhesive and/or by changing the area(s) of the adhesive-coated portion(s) of each uniting band. The purpose of changing the quantity of adhesive per uniting band is to properly relate the quantity of applied adhesive to the permeability of the web of tipping paper and/or to properly relate the quantity of adhesive to the force with which certain portions of a uniting band must adhere to the filter mouthpiece, to the plain cigarette and/or both. The patented machine is further provided with means for intermittently interrupting the application of adhesive to the running web of tipping paper. This is accomplished by resorting to a rotary cam the RPM of which is related to the speed of the running web of tipping paper and which serves to alternatingly move the running web toward and away from the adhesive applying nozzle.
The patented apparatus exhibits certain drawbacks, especially as far as its versatility is concerned. For example, the patented apparatus applies adhesive to those portions of the running web which are not to be bonded to constituents of filter cigarettes. Furthermore, the patented apparatus increases the rate of application of adhesive immediately subsequent to each interruption of transfer of adhesive to the running web of tipping paper.
The aforementioned German patent also discloses a method of applying adhesive to a running web of tipping paper. The method involves the utilization of at least one nozzle with an orifice which discharges adhesive into contact with the running web of tipping paper. The method does not take into consideration the possibility of injury to a smoker, e.g., when the filter cigarette is smoked all the way to the end of the tobacco-containing part (i.e., to the end of the plain cigarette forming part of the filter cigarette). Combustion of the inner end of the tobacco-containing part of the filter cigarette can result in the development of flame (due to combustion of adhesive which forms part of the adhesive coat on the inner side of the convoluted uniting band), and such flame can cause injury to and can frighten the smoker. Moreover, once the tobacco-containing part of a filter cigarette is combusted close or very close to the end portion which is surrounded by the respective terminal portion of the convoluted uniting band, the glowing remaining part of the tobacco-containing portion is likely to fall to the floor or onto a chair or table or suit or dress with resulting damage to the carpet, to the piece of furniture or to the clothing and the danger of fire.
A further drawback of the patented method and apparatus is that the accuracy and predictability of the application of adhesive decrease when a tipping machine turns out filter cigarettes at a rate which can be achieved by resorting to modern high-speed tipping machines. This results in the making of a high percentage of rejects as well as in customer complaints.
An object of the present invention is to increase the predictability of the application of adhesive to running webs of wrapping material, such as tipping paper which is utilized in filter cigarette making machines.
Another object of our invention is to provide a method which can be resorted to for the application of adhesive to a running web of tipping paper or the like and which renders it possible to economize with the adhesive regardless of the complexity of the pattern which is formed by applied adhesive at one side of the web.
A further object of the invention is to provide a method which renders it possible to accurately select and/or alter the pattern formed by the adhesive at one side of a web of tipping paper or the like.
An additional object of the invention is to provide a method which renders it possible to impart to the adhesive desirable qualities and/or characteristics which were not known up to this time and/or which cannot be achieved by resorting to heretofore known and practiced methods.
Still another object of the instant invention is to provide a method which renders it possible to greatly reduce the likelihood of injury to and/or startling of the smoker as well as the possibility of damage to furniture, carpeting and/or clothing at the location(s) where filter cigarettes are being smoked in offices, at homes and/or elsewhere.
A further object of the invention is to provide a novel and improved apparatus for the application of flowable adhesive to running webs of paper or the like, such as webs of tipping paper for use in filter cigarette making machines.
Another object of the invention is to provide an apparatus which can properly and predictably apply one or more types of adhesive to a running web of tipping paper in modern high-speed tipping and/or analogous machines for the making of filter cigarettes, other smokers"" products (such as cartons or packets for smokers"" products), or products which are not classifiable as smokers"" products but do employ or require the application of accurate patterns of adhesive substance(s) onto running webs of wrapping or other absorbent and/or foraminous material.
An additional object of the invention is to provide an apparatus which can be readily adjusted or converted for the application of one, two or more types of adhesive to different webs of adhesively bondable material and which can be installed in existing machines (such as the aforementioned tipping machines) for the making of various products including but not limited to smokers"" products.
A further object of this invention is to provide rod-shaped smokers"" products which are safer, more pleasing to the eye and tastier to smokers than heretofore known smokers"" products.
Still another object of the invention is to provide an apparatus which exhibits the above-enumerated features and advantages, which can be utilized for the making of the aforementioned superior products, and which can be installed in or incorporated into existing mass-producing machines or productino lines.
A further object of the invention is to provide an apparatus which can interrupt and/or restart the application of adhesive to running webs of paper, tipping paper or the like with a degree of accuracy and predictability not achievable with presently known apparatus.
Another object of the invention is to provide an apparatus which can apply simple, complex or highly complex patterns of adhesive to a running web of paper or the like in such a way that the web is not induced or compelled to perform undesirable fluttering and/or other stray movements even when the application of adhesive takes place at a rate which is required in modern high-speed tipping machines or the like.
An additional object of the invention is to provide an apparatus which can repeatedly apply a pattern of adhesive films to one side of a running web of paper or the like in such a way that the quality of the pattern is higher than those achievable with conventional apparatus because the application of patterns is not affected by those irregularities of transport of the web which necessarily or normally develop in conventional apparatus.
A further object of the invention is to provide novel and improved filter cigarettes, filter cigars and analogous rod-shaped smokers"" products.
An additional object of the invention is to provide novel and improved valves for use in the above outlined apparatus.
One of several features of the present invention resides in the provision of an apparatus which is designed to apply a flowable adhesive to selected portions of a running web of wrapping material, especially a wrapping material of the type utilized in connection with the making of smokers"" products. A typical example of such wrapping material is so-called tipping paper which is to be subdivided into relatively short sections called uniting bands serving to connect filter mouthpieces with plain cigarettes in a filter cigarette making machine (also called tipping machine).
The improved apparatus comprises at least one source of adhesive (e.g., a tank), an applicator including at least one nozzle and having at least one adhesive-discharging orifice adjacent a course or path (hereinafter called course) for the running web, means (such as one or more groups of interconnected conduits, channels or the like) for connecting the at least one source with the applicator, and means for regulating (such regulation includes interrupting) the flow of adhesive in the connecting means. In accordance with an important and highly advantageous feature of the invention, the connecting means comprises at least one rotary valve, particularly a valve of the type wherein at least one rotor is confined in and can turn relative to a stator to thereby increase or reduce the rate of adhesive flow or to interrupt the flow of adhesive from the source to the applicator.
In a presently preferred embodiment, the at least one valve includes a valve body (stator) and at least one rotor which is disposed in and has a peripheral surface defining with the valve body at least one arcuate path for the flow of adhesive from the inlet to the outlet of the at least one valve. The peripheral surface of the rotor exhibits at least one irregularity or unevenness which is arranged to influence the flow of adhesive from the inlet to the outlet of the at least one valve. The at least one irregularity can include a recess (such as a groove) and/or at least one projection (e.g., a lobe or the like). The valve body can include or constitute a housing defining a chamber for the at least one rotor.
The applicator (such as the aforementioned nozzle) can be provided with at least one adhesive-storing chamber which communicates with the at least one orifice and can be resorted to for the purpose of regulating the quantity of adhesive being applied to unit lengths of one side of the running web. Similar or analogous results can be obtained by utilizing a nozzle with an orifice having a variable depth and/or capacity and/or another parameter which, if changed, influences the quantity of adhesive being applied to the web by the thus constructed applicator. In other words, the orifice(s) of the nozzle or nozzles is or are adjustable. For example, the arrangement can be such that the overall width of the applicator and/or of the orifice is adjustable.
The applicator, such as the nozzle(s) or a carrier for the nozzle(s), can be provided with an arcuate (such as convex) web-contacting surface which is adjacent a portion of the course for the web.
The apparatus is preferably provided with means (such as one or more pumps) which serves to adjust (such as vary) the pressure of adhesive in the connecting means.
The applicator can include or be constituted by a plurality of nozzles each having at least one adhesive-discharging orifice adjacent the course for the web. The connecting means of such apparatus can include discrete conduits each of which connects the at least one source (or a selected one of several sources) with a different nozzle. Such apparatus can further comprise means (such as two or more pumps) for individually selecting the pressure of adhesive in at least two conduits.
For example, the applicator can include at least two nozzles each having at least one adhesive-discharging orifice adjacent the course for the running web. The connecting means of such apparatus can include at least two conduits each of which connects the at least one source with a different nozzle, and the apparatus further comprises means (such as one or more pumps) for maintaining the pressure of adhesive in one of the at least two conduits at a value or level which at least approximates the pressure of adhesive in the other conduit. The connecting means can further include an additional conduit which communicates with the at least one source, and the at least two conduits have inlets which communicate with the additional conduit; the pressure maintaining means can include at least one pump which is disposed in the additional conduit upstream of the inlets of the at least two conduits.
At least a portion (e.g., at least one of several nozzles) of the applicator can be provided with a coat of a material which opposes (such as prevents) accumulations of adhesive on the applicator; this reduces the likelihood of clogging of one or more orifices and the resulting departure of actual rate of application of adhesive to one side of the running web from the desired or required rate of application.
In accordance with a desirable and advantageous additional feature of the invention, the apparatus further comprises means (such as one or more sensors and/or detectors) for monitoring at least one variable parameter of adhesive on the web. For example, the monitoring means can include means for ascertaining the quantity of adhesive being applied to the web. Alternatively, or in addition to such quantity-ascertaining monitoring means, the monitoring means can include means for generating signals denoting the monitored parameter(s) and the apparatus can further comprise means for adjusting the source and/or the applicator and/or the connecting means and/or the regulating means in response to (e.g., as a function of) such signals.
If the applicator comprises a plurality of nozzles each of which has at least one orifice, the regulating means of such apparatus can comprise a rotary valve for each nozzle. Each valve can include a valve body and a rotor which is disposed in and has a peripheral surface defining with the valve body at least one arcuate path for the flow of adhesive from the inlet to the outlet of the respective valve. The peripheral surface of each rotor can be provided with at least one irregularity (such as the aforementioned recess(es) and/or projection(s)) serving to influence the flow of adhesive from the inlet to the outlet of the respective valve. Each peripheral surface, or at least one of the peripheral surfaces, can be provided with two or more irregularities (e.g., with a projection and with a recess which at least partially surrounds the projection).
The improved apparatus or the machine which embodies or cooperates with such apparatus is provided with means for advancing the web along its course at a first speed, and with means for rotating (e.g., indexing) the rotor or rotors of the valve or valves forming part of the regulating means at a second speed. Such apparatus can further comprise means for synchronizing the operation of the advancing means with that of the rotating means.
The improved apparatus can comprise at least two sources of adhesive, e.g., a first source containing a first adhesive and a second source containing a different second adhesive. The applicator of such apparatus can comprise first and second nozzles each of which has at least one orifice adjacent the course for the web, and the connecting means of such apparatus can include at least one first conduit which serves to convey first adhesive from the respective (first) source to the first nozzle and at least one second conduit which serves to convey second adhesive from the respective (second) source to the second nozzle.
A presently preferred rotary valve of the improved apparatus can include a hollow stator and a rotor which is rotatable (such as indexible) in the stator about a predetermined axis. The stator and the rotor define an arcuate groove which is disposed in a plane normal to the predetermined axis and extending from the inlet to the outlet of the valve. The groove can extend along an arc which is close to but is less than 360xc2x0.
The applicator of the improved apparatus can comprise a plurality of nozzles each of which is provided with at least one orifice and each of which is adjacent a different portion of the course for the running web. The connecting means of such apparatus can include a plurality of conduits, at least one for each of the nozzles and each connecting the source or one of several sources with the respective nozzle. For example, the source of such apparatus can include a plurality of discrete sources of different adhesives, and the aforementioned conduits can include at least two conduits connecting one of the discrete sources with the respective nozzles. The regulating means of such apparatus can include a plurality of valves each of which has a hollow body and a rotor which is turnable in the respective body about a predetermined axis; the peripheral surface of each rotor defines with the respective valve body a path leading to one of the nozzles, and the valve bodies co-operate with the respective rotors to confine the adhesive to flow along the prescribed paths, namely to the respective nozzles.
The rotors of valves in the just discussed apparatus can constitute disc-shaped sections of a rotor which is common to all valves of the regulating means. Furthermore, the hollow bodies preferably form part of a stator which is common to and surrounds all of the disc-shaped sections, and the peripheral surface of each disc-shaped section can be provided with at least one irregularity which serves to influence the flow of adhesive within the respective hollow body.
At least one of the disc-shaped sections can cooperate with the respective hollow body to establish a seal against leakage of adhesive from the respective valve. Still further, the internal surfaces of such hollow bodies (i.e., the surfaces surrounding the respective rotors) can be provided with arcuate grooves for the flow of adhesive along the respective paths; the centers of curvature of such grooves are or can be disposed on the predetermined axis. Each such groove can extend along an arc which approximates but is less than 360xc2x0. As already mentioned hereinbefore, at least one of the nozzles can be provided with at least one adhesive-storing chamber which communicates with the respective orifice.
Another feature of the invention resides in the provision of a method of applying adhesive to selected portions of one side of a web, particularly a web of wrapping material for smokers"" products. The improved method comprises the steps of advancing the web lengthwise along a predetermined course, placing first and second nozzles adjacent the one side of the web in a predetermined portion of the course, establishing first and second sources respectively containing first and second flowable adhesives, conveying adhesives from the first and second sources to the first and second nozzles, and utilizing the first and second nozzles for the application of first and second adhesives to the selected portions of one side of the web in the course.
The conveying step can include inducing the flow of first and second adhesives to the respective nozzles along discrete first and second paths, and the utilizing step can include intermittently applying at least one of the adhesives to the one side of the web in its course. Such step of intermittently applying at least one of the adhesives can include regulating the flow of the at least one adhesive by a rotary valve. The conveying step can be carried out by utilizing at least one pump for each of the first and second adhesives. In accordance with a presently preferred embodiment, the conveying step includes conveying the first and second adhesives along discrete first and second paths, and such method can further comprise the step of introducing into the adhesive at least one additive (such as a flavoring agent and/or a substance which prevents adhesive from adhering to parts of the valve(s) and/or nozzle(s)) in at least one of the first and second paths.
A further feature of our invention resides in the provision of a method of making rod-shaped smokers"" products wherein a tubular envelope confines smokable material and at least a portion of the envelope consists of a section of a web of paper or the like one side of which is at least partially coated with at least one film of an adhesive. This method comprises the steps of advancing the web lengthwise along a predetermined course, establishing at least one source of flowable adhesive, positioning an orifice of at least one nozzle adjacent a portion of the course at one side of the advancing web, conveying adhesive along at least one path extending from the at least one source to the at least one nozzle, and regulating the flow of adhesive in the at least one path. This regulating step includes employing at least one rotary valve.
An additional feature of the invention resides in the provision of a method of making rod-shaped smokers"" products wherein a tubular envelope confines a smokable material and at least a portion of the envelope consists of a section of a web one side of which is at least partially coated with at least one film of adhesive. This method comprises the steps of advancing the web lengthwise along a predetermined course, positioning the orifices of at least two nozzles adjacent a portion of the course at one side of the web, establishing at least two sources of flowable adhesive, and conveying flowable adhesive from each of the sources along a discrete path to a different one of the nozzles. Such method can further comprise the step of maintaining the adhesives in the paths at different pressures.
Another feature of the present invention resides in the provision of a novel article of manufacture which is a rod-shaped smokable product including a smokable filler and a tubular envelope consisting at least in part of a section of a web having one side at least partially coated with at least one film of adhesive. The at least one film contains at least two different types of adhesive.
At least one of the two or more different types of adhesive can consist, at least in part, of a combustion retarding material. Furthermore, at least one of the adhesives can contain a flavoring agent.
The filler can consist of cigarette tobacco and a filter mouthpiece, i.e., the smokable product can constitute a filter cigarette.
The aforementioned section of the web can constitute a convoluted uniting band of tipping paper which serves to attach one end portion of a plain cigarette to one end portion of a filter mouthpiece. Such band can include a first annular portion which is at least partially coated with adhesive containing at least one flavoring agent, and a second annular portion at least partially coated with adhesive consisting of or containing a combustion retarding material.